The present invention relates to in-line flow-control valves which seal against the flow of fluid through the valve. Arrangements of this general type are shown in the prior art U.S. Pat. Nos. 263,330; 341,170; 2,556,583; 2,709,566; and 2,883,150. None of these prior art patents teaches a valve formed of a separable body and fitting which define a cavity to house a rotatable seal assembly operable to control fluid flow.